understanding cpu usage and how to improve...

[Frank_red]

Hi,

I just watched the behavior of the CPU usage during simulation.

I have an intel Core i7 920 OC to 3.2Ghz.

the simulation start and it uses the 13% of the cpu. when it reaches the advect velocities it boost up to 98% and one the Advect fiedls are done it drops again to 13%....

I'ld like to know if it's normal and if it's possible to improve...because it takes 2 min per frame for the simulation, but during 1min 25 sec the cpu is only at 13% ....

Maybe it's important to say that this scene use a particles set up.

Thank you for the attention.

Fra.

[jrand]

Ram is almost more important than CPU count/usage, if you have to cache to disk at any point in time your CPU is going to drop because of i/o bottleneck slowing things down. Also as I am sure your have noticed the simulation is done in stages, what you see with the drops ins usage correlates with each stage doesn't it?

[Jordan]

Like jrand said, have a look at the stages. Maybe its waiting on pFlow do calculate and since pFlow is not multithreaded then you would see cpu usage dropping to one core (100%/4 cores = 25% or if you have HT on 100%/8 cores = 12.5%).

[sitnisati]

Hello,

Well, applying sources is not multithreaded as well as saving data. Those two are the only parts of the program that does not use all the CPU power.

Kresimir

[Frank_red]

Thanks for the explanations, it makes sense.

I use a cache operator for the particles as I know it still single thread... I hope it changes some time soon.

I got 12GB ram and a velociraptor as cache disk... I must check all settings.

But my cpu is the week point as I do not keep it OC all the time as lately it played me few strange tricks...I'll be updating the cpu for a better core/ghz set up.

Thanks everyone for the help.

Fra.